
CHAPTER 1 OVERVIEW
User’s Manual U14579EJ2V0UM
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(4) DMAAU (DMA Address Unit)
The DMAAU controls the addresses of DMA transfers that are used by the audio interface (MIC, speakers).
(5) DCU (DMA Control Unit)
The DCU controls the arbitration of DMA transfers that are used by the audio interface (MIC, speakers).
(6) CMU (Clock Mask Unit)
The CMU controls the supply of PCI clock (PCICLK), PIB bus clock (TClock, internal), and 48 MHz clock
pulses to internal peripheral units. TClock is a clock having the same speed and timing as the PCI clock.
(7) ICU (Interrupt Control Unit)
The ICU controls interrupt requests that are generated due to external and internal sources and reports
interrupt requests to the VR4122. Interrupts from the various on-chip macros of the VRC4173 are requested by a
single level interrupt signal, and the source is determined according to the ICU register.
(8) GIU (General-purpose I/O Unit)
The GIU controls the 21 GPIO pins.
(9) PIU (Touch Panel Interface Unit)
The PIU controls an on-chip A/D converter and detects touches on the touch panel.
(10) AIU (Audio Interface Unit)
The AIU controls on-chip A/D and D/A converters and controls MIC sampling and audio output.
(11) KIU (Keyboard Interface Unit)
The KIU, which has 12 scan lines and 8 detection lines, can detect 64, 80, or 96 key inputs.
The scan lines are exclusively used relative to the PS2U. When the PS2U is used with 1 channel, the KIU
supports 64 or 80 keys. When the PS2U is used with 2 channels, the KIU supports 64 keys.
(12) PS2U (PS/2 Unit)
The PS2U controls the PS/2 (Personal Computer Standard Keyboard) interface with two channels, PS2CH1
and PS2CH2.
The PS2U is exclusively controlled relative to the key scan lines of the KIU. When the PS/2 is used with 1
channel, the KIU supports 64 or 80 keys. When the PS/2 is used with 2 channels, the KIU supports 64 keys.
(13) ADU (A/D Converter Unit)
The ADU provides an interface with the on-chip A/D converter of the VRC4173. This A/D converter is a serial
comparison type.
(14) CARDU1, CARDU2 (PC Card Units)
The CARDU1 and CARDU2 control the 16-bit PC card interface, which is compliant with the 1997 PC Card
Standard. The 32-bit PC card (CardBus card) is not supported.
(15) USBU (Universal Serial Bus Unit)
The USBU controls the USB interface, which is compliant with Open HCI Specification Release 1.0.
(16) AC97U (AC97 Unit)
The AC97U controls the AC-Link, which is compliant with AC97 (Audio Codec ’97) standard Rev 2.1.